Pancreatic Exocrine Secretions And Control

Question 1

What are the types of cells in the pancreas?

Answer 1

Acinar cells
Pancreatic acini
Duct cells
Pancreatic islet cells

Question 2

What do pancreatic islet cells secrete?

Answer 2

Hormones

Question 3

What do duct cells secrete?

Answer 3

NaHCO3

Question 4

What do pancreatic acini cells form?

Answer 4

The exocrine portion of the pancreas

Question 5

What do acinar cells secrete?

Answer 5

Digestive enzymes

Question 6

What effect does CCK have on acinar cells?

Answer 6

Stimulatory- causes them to secrete pancreatic enzymes

Question 7

What are the levels (smallest -> biggest) of acini -> pancreatic duct?

Answer 7

Acini
Sacs
Microvilli
Intercalated ducts
Intralobular ducts
Interlobular ducts
Pancreatic duct

Question 8

Where does the pancreatic duct enter the duodenum?

Answer 8

Common bile duct

Question 9

What are the intercalated ducts in the pancreas made up of?

Answer 9

Squamous epithelium

Question 10

What are the intralobular ducts in the pancreas made up of?

Answer 10

Cuboidal or low columnar epithelium

Question 11

What are the interlobular ducts in the pancreas made up of?

Answer 11

Columnar epithelium/ goblet cells

Question 12

How much fluid does the pancreas secrete per day?

Answer 12

1.5 litres

Question 13

What is in pancreatic secretions?

Answer 13

Sodium and HCO3- rich, albumin, globulin and digestive enzymes

Question 14

Why are some enzymes secreted in an inactive form?

Answer 14

To prevent autodigestion

Question 15

What are inactive enzymes called?

Answer 15

Zygmogens

Question 16

Where does enzyme activation happen?

Answer 16

Duodenum

Question 17

What are the anions in pancreatic juice?

Answer 17

HCO3-, Cl-, SO4 2- and HPO4 2-

Question 18

What are the cations in pancreatic juice?

Answer 18

Na+, K+, Ca 2+, Mg 2+

Question 19

How is the composition of pancreatic juice modified as it travels through the duct?

Answer 19

Epithelial cells actively exchange Cl- for HCO3 -

H+ actively eliminated by Na +/K+ exchanger, exchanged for K+ by Na+/K+ ATPase and neutralises HCO3 -

Question 20

What is [HCO3 -] in pancreatic juice and its rate of production inversely proportional to?

Answer 20

[HCO3 -] blood

Question 21

What decreases in pancreatic juice when secretin increases?

Answer 21

Amylase and chloride ions

Question 22

What does a secretin stimulated pancreas cause?

Answer 22

[HCO3 -] rich secretions

Question 23

What are the 5 types of enzyme secretion in the pancreas?

Answer 23

• proteolytic enzymes
• amylase
• lipase
• ribonuclease
• deoxyribonuclease

Question 24

What does colipase do?

Answer 24

Works with lipase to break down fat droplets

Question 25

When are enterokinases secreted?

Answer 25

In response to CCK

Question 26

Where are enterokinases found?

Answer 26

Brush border of epithelial cells

Question 27

What do enterokinases do?

Answer 27

Trypsinogen -> trypsin

Question 28

What does trypsin do?

Answer 28

Causes an autocatalytic chain reaction ( autoactivation and activation of other proenzymes)

Question 29

What are the inhibitors of enterokinases?

Answer 29

KaZal inhibitor, enzyme Y | Intracellular pH of zymogen granule- acidic

Question 30

What happens in acute pancreatitis?

Answer 30

Trypsin activates phospholipase A2 in the pancreatic duct

Question 31

What does isolethicin do?

Answer 31

Disruption of pancreatic tissue, membrane damage and necrosis

Question 32

What does acute pancreatitis lead to?

Answer 32

Increased [pancreatic alpha amylase] in blood

Question 33

What happens if there is a pancreatic insufficiency of lipase?

Answer 33

Poor digestion and malabsorption of lipids

Question 34

What are the percentages of pancreas secreted enzymes that reach the small intestine?

Answer 34

Amylase- 75% Trypsin- 20% Lipase- 1%

Question 35

What 4 things control pancreatic secretions?

Answer 35

Neuroendocrine signals, vagal (parasympathetic) stimulation, sympathetic stimulation, secretin and CCK

Question 36

What happens in the pancreas when the parasympathetic systems stimulated?

Answer 36

Enhances rate of secretion of enzymes and various components of pancreatic juice

Question 37

What control of pancreatic secretions happen in the cephalic phase?

Answer 37

Vagal stimulation of gastrin release from the antrum -> protein rich pancreatic juice

Question 38

What control of pancreatic secretions happen in the gastric phase?

Answer 38

Distension, amino acid and peptide stimulated gastrin secretion -> enzyme rich pancreatic juice

Question 39

What does CCK do to the gall bladder?

Answer 39

Contracts it and relaxes the sphincter of oddi-> release of bile into the duodenum

Question 40

What happens in the pancreas in cystic fibrosis?

Answer 40

The pancreas has blocked pancreatic ducts and intestines cannot absorb nutrients properly